1. Programming Technology Lab, VUB
October 5, 1999
Programming Technology Lab, VUB
State of the Art in Reuse
and
Reuse in Practice
Aha erlebniss uitleg

2. Programming Technology Lab, VUB
October 5, 1999
Programming Technology Lab, VUB
State of the Art
Why reuse?
Current reuse approaches
Applying reuse
(Technical) problems with reuse

3. Programming Technology Lab, VUB
October 5, 1999
Programming Technology Lab, VUB
Why reuse?
Legacy Code
hard to maintain
difficult to adapt
no clear structure
cost comes at the end
Reusable Assets
easy maintainable
robust under change
well defined structure
investment up front

4. Current Reuse Approaches
October 5, 1999
Programming Technology Lab, VUB
Current Reuse Approaches
copy & paste
functional libraries
the oo paradigm
component technology
application frameworks
copy & paste
functional libraries
the oo paradigm
component technology
application frameworks
copy & paste
functional libraries
the oo paradigm
component technology
application frameworks
copy & paste
functional libraries
the oo paradigm
component technology
application frameworks
copy & paste
functional libraries
the oo paradigm
component technology
application frameworks

5. Applying reuse Storing and describing reusable artefacts
October 5, 1999
Programming Technology Lab, VUB
Applying reuse
Storing and describing reusable artefacts
Identifying the appropriate artefact
What are its properties?
How to find it?
Where to find it?
Adapting the selected artefact
What to adapt?
How to adapt it?
Managing evolution of reused artefacts
Optimal evolution =
maximisation of reuse + minimisation of time-to-deliver

6. Programming Technology Lab, VUB
October 5, 1999
Programming Technology Lab, VUB
Problems with reuse
behavioural descriptions
impact analysis
compliance checking
Last 3 points need correct solution on 1st point

7. Programming Technology Lab, VUB
October 5, 1999
Programming Technology Lab, VUB
Reuse in Practice
Practical context
InfoCAHB approach
OO application framework
Code generator
Search for solutions to technical problems
Conclusion

8. Programming Technology Lab, VUB
October 5, 1999
Programming Technology Lab, VUB
Practical Context
Case: InfoCAHB
Context: administrative application for Ministry of Justice (Courts of Appeal)
Problem: permanent evolution of legislation
Size:
LOC >
NOC > 500
5.000 man days
Approach:
OO application framework
Code generator

9. OO application framework
October 5, 1999
Programming Technology Lab, VUB
OO application framework
“An application framework is a collection of co-operating classes that make up a reusable design solution for a given problem domain.”
[Cotter&Potel95]

10. Programming Technology Lab, VUB
October 5, 1999
Programming Technology Lab, VUB
Code generator
advantages
coding standard
elimination of “slave tasks”
generated code is compliant with model
gain of coding speed (factor 3-5 in our case).
features
model enhancement (GUI, persistence)
target language independent
problems
lack of active compliance checking
need for change management
Don’t forget to mention that model enhancement provides an important kind of reuse (of GUI and persistency components).

11. Programming Technology Lab, VUB
October 5, 1999
Programming Technology Lab, VUB
Search for solutions
behavioural descriptions
impact analysis
compliance checking

12. Behavioural descriptions
October 5, 1999
Programming Technology Lab, VUB
Behavioural descriptions
“light weight” formal approach
explicit information
on behaviour
on collaboration between artefacts
on incremental modifications and evolution
allow automated reasoning in tools for
conflict detection
impact analysis
compliance checking
Reuse contracts

13. Programming Technology Lab, VUB
October 5, 1999
Programming Technology Lab, VUB
Impact analysis
Precondition: behavioural descriptions must be formalised and processable
tool support
simulation of changes
conflict detection
impact analysis
applying changes
formal metrics

14. Programming Technology Lab, VUB
October 5, 1999
Programming Technology Lab, VUB
Compliance Checking
Precondition: behavioural descriptions must be formalised and processable
types of constraints that can be verified
structural constraints
business rules/constraints
Tool support
active tools to enforce compliance at the level of the IDE
passive tools to verify compliance for a posteriory checking
proactive compliance checking by using generator

15. Programming Technology Lab, VUB
October 5, 1999
Programming Technology Lab, VUB
Conclusion
Reuse in practice can work but :
needs effort
needs investment
needs a specific company culture
technical problems need to be solved
cf. CCOOS project with Programming Technology Lab at VUB
To conclude, we want to stress that even when all technical problems would be solved, this is still no guarantee for reuse to work in practice. A specific company culture is required in order to make reuse common practice. The company needs to invest in reuse and ...

16. Programming Technology Lab, VUB
October 5, 1999
Programming Technology Lab, VUB
Contacts
Code Generator :
R. Harmegnies
Reuse contracts :
Programming Technology Lab at VUB
Kim Mens
Bart Wouters
Tom Mens
Management issues:
A. Grijseels

17. Programming Technology Lab, VUB
October 5, 1999
Programming Technology Lab, VUB
Questions